Cam actuated work clamp means movable continuously in a rotary path



la 23, 1958 H. E. :HammamA 2,820,973

v CAM ACTUATED WORK CLAMP MEANS MOVABLE CONTINUOUSLY IN A ROTARY PATH Filed Aug. 3, 1955 v 5 Shee'ts-Sheet l WM fw- 1 'ArroRNEx Jan. 28, 1958 H. E. FARMER' CAM ACTUATED WORK CLAMP mms MovABLE CONTINUOUSLY IN A ROTARY PATH 5 Sheets-Sheet 2 Filed Aug. 3, 1955 Jan. 28, 1958 H. E. FARMER CAM ACTUATED woRx CLAMP MEANS MovABLE l coNTmuousLY IN A ROTARY PATH 5 Sheets-Sheet 3 Filed A`ug. 5, 1955 Jan. 28, 1958 H. E. FARMER A CAM AGTUATED WORK CLAMP mus Momma v CONTINUOUSLY IN A ROTARY PATH Filed Aug. 3, 1955 5 Sheets-Sheet 4 mm Nw m ff E fm E Jan; Z8, 1958 H. E. FARMER v 2,820,973

CAM AGTUATED WORK CLAMP MEANS MOVABLE CONTINUOUSLY IN A ROTARY PATH 5 Sheets-Sheet 5 Filed Aug. 3, 1955 INVENTOR. .wcs E. FJHMER.

l Twelve-x United States, Patent' FO F CAM ACTUATED WORK CLAMP MEANS MOV- ABLE CONTINUOUSLY IN A ROTARY PATH Horace E. Farmer, Howell, Mich.

Application August 3, 1955, Serial No. 526,222

3 Claims. (Cl. 10-107) This invention relates generally to automatic machine tool machinery and particularly to thread cutting machines.

It is the principle object of my invention to provide an improved machine for threading the shanks of workpieces by an arrangement such that this operation may be performed eciently on a high production basis.

Another object of the invention resides in having a rotatable workpiece carrier or trunnion which rotates continuously, as opposed to the station to station movement formerly employed, whereby a continuous ow of threaded parts is produced by the machine.

Another object of the invention is to utilize the continuous rotating movement of the workpiece carrying trunnion to actuate automatically a workpiece xture clamp; to rotate thread cutting dies; and to advance and retract the dies with respect to the workpieces.

Other objects of the invention will become ,apparent from the following description, taken with the accompanying drawings in which:

Fig. l is a side elevational view having parts broken away and in section of my thread cutting machine;

Fig. 2 is a fragmentary enlarged section taken along line 2 2 of Fig. 1;

Fig. 3 is a front view partly broken away and in section, taken along line 3 3 of Fig. l;

Fig. 4 is a fragmentary plan view of one of the thread cutting dies and associated parts;

Fig. 5 is a vertical section, taken along line 5 5 of Fig. 1; v

Fig. 6 is an enlarged view in section, taken along line 6 6 of Fig. 3;

Fig. 7 is a side View partly broken away and in section of a holding fixture of the machine;

Fig. 8 is a front view partly broken away of the fixture;

Fig. 9 is an enlarged, fragmentary view of the fixture;

Fig. 10 is an enlarged, vertical fragmentary section showing details of a valve, and

Fig. ll is a cross sectional viewof the valve, taken along lines 11-11 of Figs. l and l0.

Referring to the drawings by characters of reference, my thread cutting machine comprises, in general, a .support or base having front and rear uprights or standards 22 and 24 respectively which support a horizontal 2,820,973 Patented Jan. 28, 1958 otherwise secured to base 20, as shown more clearly in Fig. 5.

Intermediate its front and rear ends, the trunnion 28 has a drum 40 of larger diameter than the trunnion proper which drum carries a number of radially spaced tool holders 42 adjacent the outer periphery thereof. Each of the tool holders 42 includes a movable member or carrier 44 which may be in the form of a tube or sleeve, as shown. These carriers 44 have their longitudinal axes parallel to the axis of rotation of the trunnion 28 and extend through the front of the drum 40. Bushings 46 in the drum 40 receive the carriers 44, the carriers being arranged to slide axially on the bushings or longitudinally of the drum axis during the thread cutting operation to etect the lead of the thread.

Carried by each of the carriers 44 is a rotatable shaft 48 which is concentric with the carrier and is journaled for rotation therein on Suitable bearings 5l). At the front of the machine, the shafts 48 project from the carriers 44 and afxed to the projected end of each shaft 48 is a i suitable threading die 52. The other or rear ends of shafts 48 project from the drum 40 into a gear casing 54 formed by the rear drum wall and a housing 56 secured thereto. Within gear casing 54, the die carrying shafts 48 have reduced end portions 58 and fixed to each, such as by splines, is a gear 60. Adjacent to each of the shafts 48 is a stub shaft 62 which is carried by the drum and has one end fixed to the drum rear wall such that the shafts 48 and stub shafts 62 are parallel. Within the gear casing 54, a rotatable sleeve gear 66 is journaled for rol tation on each of the stub shafts 62 and keyed, as at 68,

Y it will be seen that rotation of drum 4l) effects driving of shaft 26 therebetween. The shaft 26 is held against rotaand in turn may be driven by an electric motor and suitable speed reduction mechanism (not shown). Between the rear standard 24 and the trunnion 2 8, a housing 38 encloses the worm wheel 34 and gear 36, and is bolted or the several gears including drive gear 72, sleeve gear 66, gear 70 and gear 69 thereby to drive or rotate all of the die carrying shafts 48.

Within the drum 4i), a cam member 74 in the form of a ring or sleeve is iixed to the outer periphery of a ring-like holder 76 which has a hub 78 that fits over and is keyed as at 79, to shaft 26 to hold the cam member against rotation. In the outer surface of the cam member 7 4 and extended continuously around the cylindrical surfaces is a cam groove 8i) to advance the die carriers 44 in accordance with the lead of the thread to be cut and to retract the carriers after the thread cutting operation. Fixed to the outer periphery of each of the carriers 44 is a cam follower 82 engaging in the cam groove 80. Split clamps S4 may be used to clamp the followers 82 to the carriers 44, the followers 82 being rotatable on shafts 86 which screwthread into the clamps and are held against movement by set screws 88 (see Fig. 6). It will now be seen that when the trunnion 28 is rotating it rotates the die carrying shafts 48 through the individual gear trains provided therefor and also moves the carriers 44 axially by means of the cam groove S0 and followers 82. The cam groove is designed such that it moves each of the carriers 44 axially as the shaft 48 carried thereby is rotating the die, thus imparting a helix movement to cut the thread, the lead of the thread being determined by the design of cam 8G and the speed of rotation of shafts 48.

` Carried by the trunnion 28 is a number of radially spaced workpiece holding xtures 90 which are respectively aligned with the thread cutting dies 52. In the present instance, the workpiecesare pinion drive shafts 92 having an outer shank end 94 on which the machine cuts the desired thread as the thread cutting dies and xtures rotate during one revolution with the trunnion.. The

tures 90 are alike and are mounted on the trunnion at the front .of the l.machine for .convenient access 'by an attendant whose job is simply to remove the finished workpieces and replace them with unthreaded workpieces as the trunnion rotates. 96 which preferably is provided with spaced aligned wear bushings 98 to receive the workpiece 92.

A locking member or .clamp 100 provided for veach fixture is automatically actuated byrotation ofthe trunnion 28 to hold each shaft 92 `tightly :to vits holder .9.'6

during the thread cutting operation. As shown, 'the'cl'amp 100 in rod form is arranged such'tha't when moved upwardly the upper end Ythereof makes wedging .contact with the outer end of the workpiece .9.2 urging the workpiece inwardly Vand .tightly against the bushings 98.` The clamp 100 is formed with a gear rack 102 extending therealong which meshes with aV gea-r 104 on :one end of a shaft 106 such that rotation of the vshaft 106 in one direction moves .the clamp upwardly .to cla-mp the workpiece 92 to its holder, and rotation of the shaft l106 in the opposite direction withdraws .the clamp, 100 *to -release'the workpiece 92. `On the other end of shaft 106 is a gear 108 .which meshes with a 'gear rack 1110 'that is formed on .a clamp operator or cam lfollower' rod `112.

The fixtures each include a holder This rod 112 is reciprocated Vby a cam 114 which surrounds and is fixed to shaft 26 such as Vby means of a key 116, Fig. 1. The cam 114 Vis designed .such that as the thread cutting operation is completed on each of the Workpieces 92, the cam follower 112 movesto rotate shaft 106 in a direction to retract the clamp-'100 which remains retracted suf-liciently long enough to allow the machine attendant to remove the finished piecefand place another workpiece in vthe fixture holder '96.

VIn each of the fixture holders 96, the shaft 106 is journaled therein for rotation about a horizontal axis. is shown more clearly in Fig. 7, the follower 112 has a tubular upper portion to receive a spring 116 which at its upper end has an adjustable seat 118 for adjustment of theV spring compression. Spring 116 urges the follower 112 inwardly against the cam 114, and the inner ends of the followers are preferably provided each with a roller 120 to reduce friction with the cam. With particular reference to Fig. 9, the xture clamp 100 isy preferably provided in its outer surface with a guide slot 122 which extends lengthwise of the clamp to receive a guide pin 124 so as toprevent turningof the clamp. The' guide pin 124 may be an unthreaded shank portion of a screw 126 which may be screwthreaded into 'the side of the fixture holder or body 96.

During the thread cutting operation 'on each of the Workpieces, it is desirable that a coolant be sprayed thereon and it is also desirable'that coolant ow be interrupted during the interval whenthe machine. attendant is removing a finished workpiece and vreplacing it with another to be threaded. Inl order to accomplish the above automatically, I provide a valve 130 to control flow of the coolant to the workpieces anddi'es in accordance with rotation of the trunnion` 28. The valve 130v includes a casingr132 which surrounds shaft 26 and is held thereto against rotation by `a set screw 134. Rotatable with the trunnion 28 and fitting closely over the cylindrical casing 132y is a valve member 136 which. may be connected to the 'trunnion 28 by a drive pin 138. The rotatable valve Vmember 136 is. provided with .radially spaced' bores or passages 138 connected by conduits 140 which conduct coolant to the workpieces and dies. The valve casing is provided with an inlet 142 which may be connected to a suitable source of coolant which. is usually pumped from Vthe source to the partor parts to be cooled. The inlet 142 discharges into VafchaLmber 144 in, the casing which chamber is annular or eucircles the shaft communicating with the individualoutletpas:

sages 133. On the rotatable valve member 132 is`r '4 therethrough for the interval during which the attendant .removes .a .finished workpiece .and places another .in `the fixture. The valve is designed such that coolant is a1- lowed to flow to all workpieces in the process of having the thread cut thereon.

The thread cutting dies 52 have not been shown or described in detail as such dies arev well known in the art. The present dies 52 lrefo'if the type which may be opened to .receive the shank end 94, "of the workpiece 92 and then `closed to perform the., threading operation. To open and close the dies 52 each is provided with a pair of forks 150 which are secured to "afnd rotate with the trunnionlS.v When the die carrier 44 is .moved outwardlyby cam v8i), the die will be engaged and opened by one of the forks A15'0 to receive the workpiece shank 94 and continued movement of the carrier 44 will engage the other fork 150 and close the die. It will be understood that during this time, the die is rotating sincey the trunnion 328 continuously rotates during production. When the threading operation Iis complete the ldie opensand is retracted on its carrier 44 by the cam 80.

Operation vIn -operat-iomwtheinotor. driven shaft, driving -@through the worm 36 and-worm .wheel 34 rotates `the trunnion z8 on which thelarge .gear y72 'drives or rotates 'the shafts 48 of al1 o'rithe fdie carriers simultaneously. Also, as the trunnion 28`otates,.tle VAfollowers' 112 carried by the trunnion drum 40 move-'the die lcarriers 44 axially or rcctilinearly for the purpose lof establishing the lead of `the thread being out. 'on completion ,of the thread cutting'operation on one .of the workpieces, the die 52 is opened by one of the forks .1.50 and then the' fixture clamp is retracted permitting the machine attendant to remove the workpiece 9.2 'r'l'd replace i't 'with another to ybe threaded. The .fixture clan-'ip 100 is actuated bythe trunnion yoperatedfeat-n 1.14 'and follower 1250 'to lock the workpiece ink its fixture all -of which takes place as the trunnion rotates. The trunnion opera-ted cam 80V then advances thedie -52 which `opens to receive the workpiecev shank 2.94 and closes dur-ing which- 'time the die is being rotated by the trunnion through the gear trains driven thereby. Also, theftrunnion oper-ated -cam 80advances the die at a ratte corresponding to the desired lead of the thread :being cut `and when the thread is Ycompleted one of the forks 15`0`ope`ns' vthe die'to discontinue Y the cutting operation, 'the die continuing to rotate, but

being retracted to a position to start the `cutting opera tion oni-.the next workpiece. From the above,it"sh'o'uld be understood that the` workpieces 94 are' in dierert' positions' .with respect to completeness of the operation. For example, as thel thead cutting operation on one workpiece' .is'-cornpleted andthew'orkpiece replaced, the successive workpieces inthe' fixtures are in' different stages of completion, 'so that there isv a continuous Vflow of threaded workpieces produced 'from the machine'. As previously mentioned the coolant flow control rotary valve is driven bythe trunnion 2'8 and cutsof flow' of coolant to the` tltread` and die of each lunitas it reaches thev finished position'. whereby the attendant may remove and replace the workpieces 94 while the coolant flow thereto is-tturned off..

From the above description, itfwill nowbe understood that I have provided anew and. improved. thread cutting machine ofa character such that a plurality of' work-- pieces. can. be threaded Yat the same time, but insuch a pieces coming from. the machine. The success. of this high' production operation lies in having the plurality of radially J spaced -ixturcsY and a plurality of radially spaced corresponding threading dies' motmtcxlVv on a *rotatingI trunnibn ordi'um and' operated'by the rotation whereby' a completed workpiece is producedfor eachI rctationof the trlmnion. That? is, whereas inthe present machinelv six dies are used, the machine will produce a thread on a workpiece for each 60 degrees of travel of the trunnion.

While I have shown and described my invention in detail, it is to be understood that many modications and variations may be made without departing from the spirit and scope of the invention.

I claim:

1. In a tool operating machine, a support, a fixed cam on said support, a trunnion mounted on said support and rotatable about said fixed cam, a workpiece holder carried by said trunnion outwardly thereof, a reciprocal clamp bar carried by said trunnion and slidably guided thereby, said clamp bar movable lengthwise thereof relative to said trunnion between workpiece clamping and releasing positions, a radially reciprocal carn follower carried by said trunnion and reciprocal by said cam, said follower spaced from said clamp bar axially of said trunnion, and gear and rack means operatively connecting said cam follower and said clamp bar.

2. In a tool operating machine, a support, a fixed cam on said support, a trunnion mounted on said support and rotatable about said fixed cam, a workpiece holder carried by said trunnion outwardly thereof, a reciprocal clamp bar carried by said trunnion and slidably guided thereby, said clamp bar movable lengthwise thereof relative to said trunnion between workpiece clamping and releasing positions, a radially reciprocal cam follower carried by said trunnion and reciprocal by said cam, said follower spaced from said clamp bar axially of said trunnion, a shaft rotatably mounted on said trunnion and extending between said cam follower and said clamp bar, and means on said cam follower and shaft and on said clamp bar and shaft operatively connecting said cam follower and clamp bar together.

3. In a tool operating machine, a support, a fixed cam on said support, a rotatable trunnion on said support, a workpiece holder carried by said trunnion, a clamp bar carried by and reciprocal relative to said trunnion, said clamp bar having its reciprocal axis inclined with respect to the axis of rotation of said trunnion and cooperable with said workpiece holder to clamp and unclamp a workpiece, a reciprocal cam follower carried by said trunnion and cooperable with said cam, said cam follower spaced from said clamp bar longitudinally of the axis of said trunnion, a gear rack on said clamp bar, a gear rack on said cam follower, and gear means connecting said racks rotatably mounted on said trunnion.

References Cited in the tile of this patent UNlTED STATES PATENTS 52,415 Hubbard Feb. 6, 1866 372,541 Kennedy Nov. 1, 1887 490,901 Crehan Jan. 31, 1893 504,971 Disston Sept. 12, 1893 1,090,299 Harrington Mar. 17, 1914 1,159,790 Oster Nov. 9, 1915 1,508,974 Jackson Sept. 16, 1924 1,990,188 Kabbel Feb. 5, 1935 2,740,973 Borner Apr. 10, 1956 2,759,202 Marsden Aug. 21, 1956 

